The invention relates to cooling of rack-mounted devices.
Each year in the communications and information technology industries, more equipment is arranged to be housed in rackmount enclosures. Equipment housed in these rackmount enclosures produces heat, in large part due to the number of transistors in this equipment. Moore""s Law regarding transistors has held true since Intel(copyright) chairman Gordon Moore first proposed this law in 1965: the number of transistors on a micro chip will double every 18 months. The number of transistors is proportional to the thermal load each chip produces, and these chips are prevalent in rack-mounted equipment. Furthermore, operational system advances have allowed more chips to be used in multiprocessing applications, making each server produce even more heat. Thus, technological advances in chip design result in more heat being produced than in prior rack-mounted devices. Heat is undesirable as it affects performance and reliability of the rack-mounted components, e.g., including causing complete failures, and affects the useful life of the components. Often, the heat produced by the rack-mounted components is not evenly distributed in the rack. Unevenly distributed loads in the rack result in uneven heat production, or xe2x80x9chot spots.xe2x80x9d
In general, in an aspect, the invention provides a gas distribution unit for use in a rack that holds rack-mounted equipment that produces heat during operation. The gas distribution unit includes a housing defining a cavity, an exhaust port in a top wall of the housing, and at least one intake port configured to provide fluid communication between the cavity and a volume of gas external to the housing, the at least one intake port being at least partially laterally displaced relative to the exhaust port, the housing being configured to be disposed in and coupled to the rack and to direct gas from the cavity substantially directly upward through the exhaust port when coupled to the rack, and at least one fan coupled to and disposed within the housing and configured to draw gas through the at least one intake port, and to force the drawn-in gas out of the gas distribution unit through the exhaust port.
Implementations of the invention may include one or more of the following features. The exhaust port is defined adjacent a front edge of the housing. The housing has a curved transition between a bottom wall and a front side wall. The gas distribution unit further includes a plenum boot connected to the housing enclosing the at least one intake hole. The boot comprises a flexible material. An end of the boot that is displaced from the housing is configured to be attached to a surface defining a cool-gas port that provides access to a source of cool gas, the displaced end of the boot being configured to surround a perimeter of the cool-gas port.
Implementations of the invention may also include one or more of the following features. The housing is configured to be mounted into the rack such that a front wall of the housing is disposed adjacent to a front wall of the rack. The housing includes an interior wall that divides the cavity into a plurality of sub-cavities, and wherein the at least one fan includes at least one fan disposed within each sub-cavity. The gas distribution unit further includes multiple power inputs and a fail-over module electrically coupling the power inputs to the fans, the fail-over module being configured to disconnect a first of the power inputs from a first fan and connect a second of the power inputs to the first fan in response to a loss of power on the first power input. The at least one intake port includes at least one intake port for each sub-cavity, each intake port being associated with a corresponding fan, and wherein the fans each include a ring of fan blades configured and disposed to surround a perimeter of the corresponding intake port, each fan being configured to rotate the ring to draw gas through the corresponding intake port into an interior of the fan and to force the drawn-in gas radially outward through the ring. The gas distribution unit further includes a filter apparatus coupled to the housing and configured to filter gas drawn into the at least one intake port by the at least one fan.
In general, in another aspect, the invention provides a modular gas distribution unit for use in a rack that holds rack-mounted equipment that produce heat during operation, the rack-mounted equipment having corresponding fronts. The gas distribution unit includes in combination a housing, a fan connected to the housing and configured to draw gas from a first region external to the housing and force the gas from the first region into a second region internal to the housing, means for directing the gas forced into the second region upward adjacent the fronts of the rack-mounted equipment, and means for guiding cool gas from a source of the cool gas to the first region, the means for guiding being configured to guide the cool gas for adjustable distances to accommodate different separations between the means for directing and the source of cool gas.
Implementations of the invention may include one or more of the following features. The means for guiding includes a plenum comprising a flexible material. The means for directing includes an interior wall of the housing dividing a cavity, defined by the housing, into sub-cavities, the gas distribution unit further including at least another fan, with at least one fan disposed in each sub-cavity. The gas distribution unit further includes a redundant power distribution system coupled to provide power to the fans from multiple power sources, and to switch which power source provides power to a particular fan if the power source coupled to the particular fan fails. The gas distribution unit further includes a fan selector configured to control at least one of which combination of the fans will receive power and at which speed at least one of the fans will operate. The gas distribution unit further includes a filter apparatus coupled to the housing and configured and disposed to filter the cool gas.
In general, in another aspect, the invention provides a method of cooling equipment modules disposed in a rack of equipment modules, the modules being disposed above one another in the rack, the modules including fans to draw gas from fronts of the modules through the modules and to expel the gas from backs of the modules, the modules having corresponding fronts. The method includes drawing gas from a bottom region near a bottom of the rack, guiding the gas from the bottom region to a lower front region disposed below the fronts of the modules, and forcing the gas upward from the lower front region into an upper front region adjacent the fronts of the modules while inhibiting the gas from being initially forced into portions of the rack other than the upper front region.
Implementations of the invention may include one or more of the following features. The inhibiting comprises forcing the gas from the lower front region into the upper front region through an exhaust port configured to guide the gas into the upper front region. The guiding comprises inhibiting gas flow using a flexible plenum coupled to a surface defining an opening that provides access to cool gas, the drawing and forcing comprising drawing and forcing the cool gas. The method further includes filtering the gas drawn from the bottom region.
Various aspects of the invention may provide one or more of the following advantages. Higher volumes of colder air can be delivered to rack-mounted components than in other solutions. Reliability of rack-mounted components, e.g., servers, can be increased and hot spots reduced compared to previous designs. More components can be loaded into a rack without loss of reliability. Existing racks can be retrofitted to provide better cooling of rack-mounted components. A compact, high throughput, modular apparatus with few moving parts can be provided to new or existing racks to cool rack-mounted components. Electrical and mechanical failures of a rack-cooling apparatus are guarded against, e.g., with electrical and mechanical redundancy. Cooled air, and/or cooler-than ambient air, can be provided directly to rack-mounted equipment. The invention reduces/minimizes mixing of conditioned air with ambient air and may provide filtration. Variable amounts of cooling may be provided in response to variations of temperature and power consumption of rack-mounted components.
These and other advantages of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims.